### Abstract

The anisotropy of small-scale temperature fluctuations in shear flows is analysed by making measurements in high-Reynolds-number atmospheric surface layers. A spherical harmonics representation of the moments of scalar increments is proposed, such that the isotropic part corresponds to the index j = 0 and increasing degrees of anisotropy correspond to increasing j. The parity and angular dependence of the odd moments of the scalar increments show that the moments cannot contain any isotropic part (j = 0), but can be satisfactorily represented by the lowest-order anisotropic term corresponding to j = 1. Thus, the skewnesses of scalar increments (and derivatives) are inherently anisotropic quantities, and are not suitable indicators of the tendency towards isotropy.

Original language | English (US) |
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Pages (from-to) | 279-288 |

Number of pages | 10 |

Journal | Journal of Fluid Mechanics |

Volume | 448 |

State | Published - Dec 10 2001 |

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### ASJC Scopus subject areas

- Mechanics of Materials
- Computational Mechanics
- Physics and Astronomy(all)
- Condensed Matter Physics

### Cite this

*Journal of Fluid Mechanics*,

*448*, 279-288.

**Anisotropy of small-scale scalar turbulence.** / Kurien, Susan; Aivalis, Konstantinos G.; Sreenivasan, Katepalli R.

Research output: Contribution to journal › Article

*Journal of Fluid Mechanics*, vol. 448, pp. 279-288.

}

TY - JOUR

T1 - Anisotropy of small-scale scalar turbulence

AU - Kurien, Susan

AU - Aivalis, Konstantinos G.

AU - Sreenivasan, Katepalli R.

PY - 2001/12/10

Y1 - 2001/12/10

N2 - The anisotropy of small-scale temperature fluctuations in shear flows is analysed by making measurements in high-Reynolds-number atmospheric surface layers. A spherical harmonics representation of the moments of scalar increments is proposed, such that the isotropic part corresponds to the index j = 0 and increasing degrees of anisotropy correspond to increasing j. The parity and angular dependence of the odd moments of the scalar increments show that the moments cannot contain any isotropic part (j = 0), but can be satisfactorily represented by the lowest-order anisotropic term corresponding to j = 1. Thus, the skewnesses of scalar increments (and derivatives) are inherently anisotropic quantities, and are not suitable indicators of the tendency towards isotropy.

AB - The anisotropy of small-scale temperature fluctuations in shear flows is analysed by making measurements in high-Reynolds-number atmospheric surface layers. A spherical harmonics representation of the moments of scalar increments is proposed, such that the isotropic part corresponds to the index j = 0 and increasing degrees of anisotropy correspond to increasing j. The parity and angular dependence of the odd moments of the scalar increments show that the moments cannot contain any isotropic part (j = 0), but can be satisfactorily represented by the lowest-order anisotropic term corresponding to j = 1. Thus, the skewnesses of scalar increments (and derivatives) are inherently anisotropic quantities, and are not suitable indicators of the tendency towards isotropy.

UR - http://www.scopus.com/inward/record.url?scp=0035842091&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035842091&partnerID=8YFLogxK

M3 - Article

VL - 448

SP - 279

EP - 288

JO - Journal of Fluid Mechanics

JF - Journal of Fluid Mechanics

SN - 0022-1120

ER -